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Parameter

Description

Enabled

Enables/disables current effect.

Comment

A free-form text field for any comment on the effect.

Inheritance

Specifies the source of default (starting) parameters for the effect.

  • Standard: Uses the built-in (coded) parameter defaults. These are zero or off for most parameters, except for a few which serve as multipliers, and for which 1 is the more natural default.
  • System: (default) Reads the "System.Default" effect to use as defaults. If no such effect exists, uses Standard defaults.
  • Parent: Inherits paramUses Uses the parent particle effect for defaults. One possible use for this is to create a parent effect with one set of parameters, then a variety of sub-effects which alter some of the parameters for variation. Sub-effects can be spawned on their own. Editing the parent effect will update the default values of all sub-effects.

The Inheritance source has the following consequences:

  • When you create a new effect, it takes its default parameters from the Inheritance source, which by default is System.
  • The labels of all non-default parameters are highlighted in the Particle Editor. This allows you to quickly see which values you have actually changed.
  • If you change the Inheritance source, it does not change any other parameters. However, different parameters may be highlighted, as their defaults have changed.
  • To actually set parameters to their default values, press the Reset icon, or Reset item on the effect context menu. This can be done just after creating a new effect and changing its Inheritance value; or at any time during editing, to reset parameters to the selected Inheritance default. (Note: the Inheritance parameter itself is not changed by the Reset command.)
  • When effects are saved to XML libraries, only non-default values are saved. When they are loaded from XML, the current defaults for the effect's Inheritance are used as a base.
  • When you edit any parameters of a parent effect, the non-edited parameters of all children (and descendents) which have Inheritance = Parent will be instantly updated.
  • To customize the default effects for your game, create a System library, and a Default effect.
  • If you edit the System.Default effect, and then Save the System library, the non-edited parameters of all effects and emitters will be updated.
  • To customize the default effects for a specific Configuration, create a child of the System.Default effect, give it any name you want, set its Inheritance = Parent (not required, but helpful), set its Configuration parameters to a subset of possible configurations (e.g. VeryHigh only), and then edit its effects. When the engine looks for the default parameters to use, it looks for the deepest effect in the System.Default family which matches the current engine configuration.

 

Spawn Indirection

Contains 4 options:

  • Direct: Spawn in the normal way.
  • Parent Start: Spawn once the parent has spawned.
  • Parent Collide: Once the parent particle has collided with an object, this is the trigger to spawn a particle with this setting.
  • Parent Death: When the parent particle has lived out its lifetime, this is the trigger to spawn a particle with this setting.

Count

The total number of particles at any one time that will be active. Determines emission rate (Count / Particle Life Time).

Maintain Density

Increase emission rate (and particle count) when emitter moves to maintain the same spatial density as when motionless. The increase can be scaled from 0 to 1.

  • Reduce Alpha: When Maintain Density is active, this will reduce particle alpha correspondingly, to maintain the same overall emitter alpha. The reduction can be scaled from 0 to 1.

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Parameter

Description

Continuous

If false, all particles are emitted at once, and the emitter then dies. If true, particles are emitted gradually over the Emitter Life Time.
If true, and Emitter Life Time = 0, particles are emitted gradually, at a rate of Count / Particle Life Time per second, indefinitely.

Spawn Delay

Delays the start of the emitter for the specified time. Useful to delay sub-effects relative to the overall emitter creation time.

Emitter Life Time

If Continuous = true, specifies the life time of the emitter. 0 = infinite life time (default).

Note

Emitter Life Time does not apply to non-Continuous effects, which will always disappear as soon as they have emitted all of their particles. 


 

Pulse Period

If >0, the emitter will restart repeatedly at this interval.

 

Particle Life Time

The life time of individual particles. Even after the emitter's life time has expired, spawned particles will live out their own life time.

 

Remain While Visible

Particles in the effect will not die until the entire emitter is out of view.

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Parameter

Description

Focus Angle

The amount to rotate, in degrees from Y axis. (0 = straight up, 90 = Horizontal, 180 = straight down).

Focus Azimuth

The amount to rotate the new axis about the Y axis. (0/360 = North, 90 = West, 180 = South, 270).

Focus Gravity Camera Dir

DEPRECATED (use Gravity Scale instead)
Forces the focus direction to world Set focus direction to face camera. Amount can be scaled from 0 to 1.

Focus Gravity Dir

DEPRECATED (use Gravity Scale instead)
Force the focus direction to world negative gravity direction (usually world +Z), ignoring emitter orientation.

Focus Rotates Emitter

If true, changing the focus direction with the above parameters will also rotate rotates the orientation of the Offset parameters. If false, Offset vectors remain in emitter orientation.

Emit Offset Dir

If true, changes change each particles emission direction to be aligned with its offset from the origin.

Emit Angle

The angle deviation of an emitted particle from the focus axis (default local +Y). (0 = +Y straight up, 90 = comes out horizontal to the emitter, 180 = -Y straight down).
This is the maximum angle from the focus. The Random sub-parameter controls the minimum angle.

Examples:

  • To emit in all directions, set Emit Angle = 180, Random = 1. 
  • To emit in the top hemisphere, set Emit Angle = 90, Random = 1. 
  • To emit in a horizontal circle, set Emit Angle = 90, Random = 0.

Facing

Applies only to 2D particles, Determine how the sprite is oriented in space. Texture orientation is further modified by rotational parameters:

  • Camera: Faces the  viewer, texture X&Y aligned with screen X&Y.
    In this mode only, particles are assumed to represent spherical objects, are are lit accordingly (see Curvature below). In all other modes, particles are lit as flat polygons.
  • CameraX: Rotates about local Y axis only, to face camera as much as possible.
  • Free: Rotates freely in 3D. (Remember to give it some rotation; the default orientation is equal to the emitter's).
  • Velocity: Faces direction of movement.
  • Water: Faces upward, moved and aligned to nearest water plane.
  • Terrain: Faces upward, moved and aligned to nearest terrain location.
  • Decal: Renders the particle as an actual deferred decal, projected onto the nearest surface. (The Thickness parameter controls the projection depth.) (Only works with Materials, does not work with textures)

Orient To Velocity

Forces Texture X axis aligned to direction of movement. Rotation parameters can rotate it further.

Curvature

For Facing = Camera particles, sets how far the vertex normals are bent into a spherical shape, which affects lighting.
0 = flat, lit like a polygon. 1 = bent into an (almost) hemispherical shape, lit like a sphere, which is the default.

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Parameter

Description

Blend Type

Applies only to 2D particles. Determines how the sprite blends with the background.

  • Alpha Based: Final Color = Particle Color * Particle Alpha + Background Color * (1 - Particle Alpha).
  • Additive: Final Color = Particle Color + Background Color.
  • Multiplicative: Final Color = Particle Color * 2 * Background Color.

Texture

Browse and choose the texture used for 2D sprite particles. Displays a preview of the texture when the mouse cursor is over the input box.

Texture Tiling

Splits the texture into tiles, for variation and animation:

  • Tiles X & Y: How many tiles the texture is split into.
  • First Tile: The first of the range of tiles used by this particle (numbered from 0).
  • Variant Count: How many consecutive tiles in the texture the particle will randomly select from. 
  • Anims Frame Count: How many tiles make up an animation sequence. Variant Count and Anim Frames Count can be used together.
    For example, if Variant Count = 2 and Anim Frames Count = 8, then the particle will randomly choose between using tiles 0 through 7, or 8 through 15, as an animated sequence.
  • Anim Framerate: Frames per second for the animation. If 0, then the animation runs through one sequence in the particle lifetime.
  • Anim Cycle: If Once, the animation plays once, and holds on the last frame. If Loop, it cycles indefinitely. If Mirror, it alternates cycling forward and backward indefinitely.
  • Anim Blend: Render the particle blended between the two adjacent anim frames. Note: performance impact.
  • Flip Chance: Specifies the fraction of particles that will be rendered mirrored in texture X.

Material

Browse and choose the material used for 2D sprite particles.

Tessellation

If supported by hardware, enables tessellation, rendering more vertices within the sprite.
This is useful when Receive Shadows is set, increasing the resolution of shadows; or when Tail Length or Connection is set, creating smoother curves in connected particles.
This also helps with regards to receiving light from point lights, as the lighting will be more accurate.

Octagonal Shape

Renders sprites as octagons instead of quads, reducing pixel cost. Only to be used with textures that fit within an octagon, otherwise clipping will occur.

Soft Particle

Apply a rendering technique that softens the intersection between sprites and nearby objects, to prevent unnatural seams.
Slightly more expensive, so use sparingly on particles that need it, eg: smoke.

Geometry

Browse and choose 3D object to use for the particles.

Geometry in Pieces

If true, and the Geometry asset contains multiple sub-objects, then the geometry will be emitted in split-up pieces,
one set per particle 
Count, originating at each piece's location in the asset.
If false, each particle will use the entire geometry (all sub-objects together).

No Offset

For Geometry particles, use the geometry pivot for centering.

Alpha

The alpha blending value of Controls the particle, multiplying the texture's alpha value. 's opacity, for Blend Type = Alpha.. For Additive blending, serves as a multiplier.
Normally 0 to 1, but you can push the alpha beyond 1 to achieve a stronger effect.

Alpha Clip

A set of parameters to customize how the particle Alpha value controls opacity and/or alpha test values.

Each parameter below has 2 values, corresponding to their values when particle Alpha = 0 and 1.
They are interpolated for each particle with its Alpha value, and then used in the shader with the following equation:

FinalOpacity = saturate( (TextureAlpha - SourceMin) / min(SourceWidth, 1 - SourceMin) ) * Scale

  • Scale: A multiplier for the final alpha value. Defaults to (0, 1), so that particle Alpha directly scales final opacity.
  • Source Min: Specifies the minimum source (texture) alpha to be rendered (alpha test); values below become transparent. Defaults to (0, 0), corresponding to no alpha test.
  • Source Width: Specifies the feathering range of alpha clipping; 0 specifies hard-clipping, 1 soft-clipping. Defaults to (1, 1), corresponding to full utilization of texture alpha.

Examples:

  • Default: Alpha controls opacity, no alpha clipping: Scale = (0, 1), Source Min = (0, 0), Source Width = (1, 1).
  • Hard clipping at texture alpha = C, no feathering: Scale = (1, 1), Source Min = (C, C), Source Wdith = (0, 0).
  • Hard clipping, controlled by particle alpha: Scale = (1, 1), Source Min = (0, 1), Source Width = (0, 0).
  • Feathered clipping, with width F, controlled by particle alpha: Scale = (1, 1), Source Min = (0, 1), Source Width = (F, F).
  • Soft clipping, test value controlled by particle alpha: Scale = (1, 1), Source Min = (0, 1), Source Width = (1, 1)
  • Clipping and opacity scale, controlled by particle alpha: Scale = (0, 1), Source Min = (0, 1), Source Width = (1, 1)

Color

Pick the color to apply to the particle:

  • Random: How much a particle's initial color will vary (downward) from the default. 0 = no variation, 1 = random black to default.
  • Random Hue: Causes the Random color variation to occur separately in the 3 color channels. If false, variation is in luminance only.
  • Emitter Strength: Define the color of the particle over the emitter's life time.
    Add a keyframe color by double clicking inside the panel and assigning a color. You can add multiple keyframes into the timeline by repeated double clicks. 
  • Particle Life: Define the color of the particle over the particle's life time.
    Add a keyframe color by double clicking inside the panel and assigning a color. You can add multiple keyframes into the timeline by repeated double clicks.

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Parameters in this tab control the lighting of the particle.

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Parameter

Description

Diffuse Lighting

Multiplier to the particle color for dynamic (diffuse) lighting.

Diffuse Backlighting

Fraction of diffuse lighting that is applied to unlit particle directions.

  • 0 = standard diffuse lighting, where the normals facing the light are lit the most.
  • 1 = omnidirectional diffuse lighting, where lights affects all normals equally.

Emissive Lighting

Multiplier to the particle color for constant emissive lighting. This can make a glowish appearance to the particle by adding some value.

Receive Shadows

Allows shadows to be cast on the particles.

Cast Shadows

Allows particles to cast shadows.

Note

This is only for Geometry particles.

Not Affected By Fog

Causes particles to ignores scene fog.

Global Illumination

Allows the particle to receive global illumination from the environment.

Diffuse Cubemap

Use nearest deferred cubemap for diffuse lighting.

Light Source

Causes each particle to create a deferred light. Color is equal to the Color value.

  • Affects This Area Only: For use with Clip Volumes. When enabled, the particle lights do not exceed the volume boundary.
  • Radius: Radius of the light.
  • Intensity: Intensity of the light. 
  • HDRDynamic: Control the power to apply to engine HDR multiplier, for particle light source in HDR.

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Audio

Parameters in this tab browse and control the sound files.

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Parameter

Description

SoundStart Trigger

Browse and choose the sound asset to play with the emitter.

SoundFX Param

Modulate value to apply to the soundStop Trigger

Browse and choose the sound asset to play with the emitter.

SoundFX Param

Modulate value to apply to the sound. Its effect depends on how the individual sound's "particlefx" parameter is defined.
Depending on the sound, this value might affect volume, pitch, or other attributes.

Sound Control Time 

Control how long the sound plays:

  • Emitter Life Time: Plays for the length of the emitter's life time.
  • Emitter Extended Life Time: Plays for the length of the emitter's life time plus all particle's life times; i.e. until all particles die.
  • Emitter Pulse Period: Plays for the length of the pulse period.

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Parameter

Description

Size

For 2D particles, the world sprite radius. For 3D particles, the scale applied to the geometry.

Aspect

The X-to-Y axis ratio. Default = 1; >1 stretches in X direction, <1 in Y direction.

PivotX, PivotY

Move the pivot point of the sprite. Defaults = 0 (texture center); range +/- 1.

Stretch

The amount of stretch applied to the particle in the direction of travel, in seconds (based on current velocity). Stretches in both directions by default.

  • Offset Ratio: Adjusts the center of stretching. 0 = stretch both directions, 1 = stretch backward only, -1 = stretch forward only.

Tail Length

Length of particle's tail in seconds. Particle texture will be stretched out through the tail.

  • Tail Steps: Number of segments for tail. A higher number will produce smoother tail curves for non-linear-moving particles.
Tip

If Tessellation is set, the tail will be rendered as a smoothly interpolated curve between tail segments.

Min Pixels

Adds this many pixels to particles true size when rendering. This is useful for important effects that should always be visible even at distance.

Connection

Causes all particles to be rendered in a connected line, in sequence. Emission sequences separated by a Pulse Period produce separate polygons.
Indirect child effects produce a separate polygon for each parent particle.

  • Connect To Origin: Additionally connect the newest particle to the emitter origin, with the parameters of a particle of age 0.
  • Texture Mapping: This and the next parameter specify how textures are repeated over the stream. 
    • Per Particle sets a default frequency of one texture per particle. 
    • Per Stream sets a default frequency of one texture stretched over the whole stream.
  • Texture Frequency: Multiples the texture Mirror: Option which causes adjacent texture tiles to alternate direction; if false, they wrap at each repetition. Default = true.
  • Texture Frequency: Multiples the texture repeating frequency specified above. . Can be >0 or <0, which determines texture direction.
Tip

If Tessellation is set, the stream will be rendered as a smoothly interpolated curve between particles.


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Parameter

Description

Speed

The initial speed of particles.

Inherit Velocity

What fraction of initial velocity is inherited from the particle's parent.
For indirect particles, the parent particle's velocity is inherited. For direct particles, the emitter's velocity is inherited.

Air Resistance

How much to react against the global wind speed. Units are 1/seconds. The higher the number, the faster particles will reach wind speed (or rest if no wind).

Rotational Drag Scale

Fraction of Air Resistance applied to slow down particle rotation. If 0 (default), only particle velocity is slowed, not rotation.

Wind Scale

Multiplier to environment wind, to use when computing particle drag.

Gravity Scale

Multiple of world gravity to apply to particles. Most physicalized particles should be set to 1 (use Air Resistance to provide drag).
Set to a negative value for
buoyant particles such as smoke.

Acceleration

The constant acceleration applied to particles, in world space (X,Y,Z).

Turbulence 3D Speed

Adds a 3D random turbulent movement to the particle, with the specified average speed.

Turbulence Size

Adds a spiral movement to the particles, with the specified radius. The axis of the spiral is set from the particle's velocity.

Turbulence Speed

When Turbulence Size > 0, the angular speed, in degrees/second, of the spiral motion.

Move Rel Emitter

Forces particle motion in emitter space; particles will move with its emitter.

  • No = particle moves in world space. 
  • Yes = particle body moves with emitter, tail segments remain in world space.
  • Yes with Tail = both particle body and tail segments move with emitter.

Bind Emitter to Camera

Forces the emitter to relocate to the main camera's position. Useful (with Space Loop) for making a rain or snow effect, which the player cannot pass by.

Space Loop

Particles loop within a region around the camera, defined by Camera Min/Max Distance (under the visibility tab).
This is useful to make rain or snow effect, which has an effective infinite spawning area.

Target Attraction

Specifies if particles are attracted to a target. This causes them to orbit toward the specified target position, as controlled by the sub-parameters below. 

  • Target
    • External = particles attracted to a target entity, if the emitter is linked to one (default). 
    • OwnEmitter = particles are attracted to their own emitter's origin. 
    • Ignore = particles ignore any external attractor.
  • Extend Speed: Particles speed up to reach the target in their lifetime. Otherwise, they move at natural speed toward the target, and may not reach it. 
  • Shrink: Particles shrink as they approach the target.
  • Orbit: Particles orbit around target when reached. Otherwise, they disappear into the target.
  • Orbit DistanceRadius:  Distance from the target that particles either orbit around, or disappear.

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Parameters in this tab control the visibility of the particles.

Parameter

Description

View Distance Adjust

Multiplier to the automatically computed fade-out camera distance.

Camera Max/Min Distance

The camera range that particles render in. Defaults are 0, specifying unlimited range.

View Camera Distance Adjust

Multiplier to the automatically computed fade-out camera distance.

Draw Last

Modifies draw order of sub effects. Sub effects are rendered by lowest Draw Last value first, or in list order if equalOffset

Offset the emitter away from the camera.

Sort Offset

Bias the distance used for sorting. Can be used to customise the sort order within an emitter tree: by default sub-emitters render in the order they are listed in the effect. A bias of 0.01 or greater will override that order. Larger biases can be used to adjust the sorting order with respect to other transparent objects in the level.

Draw Near

Render particles in a near 1st-person space (with weapons etc).

Draw on Top

Render particles on top of everything (no depth test).

Visible Indoors

For use in Vis Areas:

  • If_True: Hides particles when outdoors.
  • If_False: Hides particles when indoors.
  • Both: Show particles always.

Visible Underwater

For use with the Ocean / Water Volumes:

  • If_True: Hides particles when above water.
  • If_False: Hides particles when under water.
  • Both: Show particles always.

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